logilab-doctools #4518676 Add a ReST directive for importing doc excerpt from a doc library [in-progress]

In order to ease the writing of complex documents, the user might want to import a document part from a file stored into a document library.

In ReST, the existing include directive doesn't fulfill the need because it inserts the raw lines of the inserted file into the ReST parser. Therefore, the section hierarchy (use of ===, ---, ***, etc.) must be perfectly consistent with the current document, which is impossible when inserting excerpts at different levels in the document.

The new import directive must thus parse and build the imported document tree before copying its nodes inside the target document tree.

done in0.8.0
load left4.000
closed by<not specified>